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hugetlb: remove prev_vma from hugetlb_get_unmapped_area_topdown() 

After looking up the vma which covers or follows the cached search
address, the following condition is always true:

	!prev_vma || (addr >= prev_vma->vm_end)

so we can stop checking the previous VMA altogether.

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Xiao Guangrong 2012-03-21 16:34:14 -07:00 committed by Linus Torvalds
parent 40716e2924
commit b69add218d
1 changed files with 5 additions and 13 deletions
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18
arch/x86/mm/hugetlbpage.c
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@ -308,7 +308,7 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
{ {
struct hstate *h = hstate_file(file); struct hstate *h = hstate_file(file);
struct mm_struct *mm = current->mm; struct mm_struct *mm = current->mm;
struct vm_area_struct *vma, *prev_vma; struct vm_area_struct *vma;
unsigned long base = mm->mmap_base; unsigned long base = mm->mmap_base;
unsigned long addr = addr0; unsigned long addr = addr0;
unsigned long largest_hole = mm->cached_hole_size; unsigned long largest_hole = mm->cached_hole_size;
@ -340,22 +340,14 @@ try_again:
if (!vma) if (!vma)
return addr; return addr;
/* if (addr + len <= vma->vm_start) {
* new region fits between prev_vma->vm_end and
* vma->vm_start, use it:
*/
prev_vma = vma->vm_prev;
if (addr + len <= vma->vm_start &&
(!prev_vma || (addr >= prev_vma->vm_end))) {
/* remember the address as a hint for next time */ /* remember the address as a hint for next time */
mm->cached_hole_size = largest_hole; mm->cached_hole_size = largest_hole;
return (mm->free_area_cache = addr); return (mm->free_area_cache = addr);
} else { } else if (mm->free_area_cache == vma->vm_end) {
/* pull free_area_cache down to the first hole */ /* pull free_area_cache down to the first hole */
if (mm->free_area_cache == vma->vm_end) { mm->free_area_cache = vma->vm_start;
mm->free_area_cache = vma->vm_start; mm->cached_hole_size = largest_hole;
mm->cached_hole_size = largest_hole;
}
} }
/* remember the largest hole we saw so far */ /* remember the largest hole we saw so far */